CD TOWER VU METER

Here's a simple one...

People are moving from CDs to digital files for music (or maybe 
they've already done so). As a result it's likely that many don't 
need to keep their old CDs handy in one of those classic 
frames/holder towers. You know:

 ______________________________________________________________
|  __________________________________________________________  |
| |_____________So and so's Not So Terrible Hits_____________| |
|--------------------------------------------------------------|
|  __________________________________________________________  |
| |_____________Baby my Gopher's Cold Outside________________| |
|--------------------------------------------------------------|
|  __________________________________________________________  |
| |________Fax Machine Noises for Deeply Crazed Minds________| |
|--------------------------------------------------------------|
|  __________________________________________________________  |
| |_________Songs to Manually Centre ASCII Text By___________| |
|--------------------------------------------------------------|
|  __________________________________________________________  |
| |______Was I meant to give this one back to someone?_______| |
|--------------------------------------------------------------|
|  __________________________________________________________  |
| |__________WIN XP -- key is XXXXXXXXXXXXXXX________________| |
|--------------------------------------------------------------|
|                                                              |
|                                                              |
|--------------------------------------------------------------|
|                                                              |
|                                                              |
|--------------------------------------------------------------|
|                                                              |
|                                                              |
|______________________________________________________________|

So my thinking is, there are probably lots of old CD towers going 
to waste. What if you turned one into a big VU meter instead?

Specifically: Buy a bulk pack of clear CD "jewel" cases, stick 
strips of LEDs along the side that faces the back when they're in 
the tower (maybe put in a plain white paper jacket just to diffuse 
the light), wire them up to an LM3916 chip, and you've got a big VU 
meter! You could wire multiple CD cases up to the same "bar" output 
from the LM3916 for towers more than ten levels high (hint, if you 
set the LED current below maximum brightness then the fading in/out 
of the bars works better and it can appear like multiple bars 
connected to the same output are actually fading in/out in 
sequence), or adjust the voltages so that you can use multiple 
chips.

Here's an example I found of a more complex circuit that 
multiplexes multiple audio channels through one LM3916 so that 
multiple bars can be controlled by the one chip. Might be good for 
a CD tower with multiple rows horizontally. Also notes how to add a 
peak level indicator.
http://www.all-electric.com/schematic/quad-met.htm

The idea is that the light shines inside each case and lights it up 
as a glowing bar of light, when viewed from the side that faces 
outwards when they're in the tower. I think it would look a lot 
better than just the LED strips on their own.

The trouble for me is that I still use my CD tower for old software 
that I won't part with, and I've already built an even cooler (and 
much harder to build) 3D sort of VU meter design anyway. Should be 
a nice project for someone though (be sure to email me a photo!).

- The Free Thinker, 2020.